PERSPECTIVES IN EVOLUTION RITCHIE 251 



ing to interpret life axiomatically, a difficulty which appears to be 

 insurmountable. A common ground, even if it be largely a common 

 ground of uncertainty and cautiousness, is being approached by the 

 schools of physics and biology. 



Broadly it may be said that the efforts of recent years have done 

 much to reduce the mystery of life. An elusive quality remains, but 

 the elusive quality is retreating within its shell, and its shell becomes 

 smaller and smaller, just as the corresponding physical mystery has 

 been driven from stronghold to diminishing stronghold, from mole- 

 cule to atom, from atom to proton and electron with the irreducible 

 quantum of activity. Such advances as have been made in the inter- 

 pretation of life have been due to the application of physical and 

 chemical methods and concepts. 



There have been theoretical interpretations, working hypotheses 

 founded rather on analogy than deduced from direct observation, like 

 the oscillatory theory of Lakhovsky (1929), who regards the cell as 

 an electromagnetic resonator, active in absorbing and emitting radia- 

 tions of very high frequency. Life, in his view, is the dynamic equilib- 

 rium between such cells, the harmony of innumerable radiations react- 

 ing upon each other. Or the vortex theory of Lartigue (1929) who, 

 endeavoring to extend to the domain of life the laws of eddies, comes 

 to the conclusion that the living organism is not an ordinary thermal 

 machine, since it works at a temperature practically constant, nor an 

 ordinary electrical machine, since it works at a practically constant 

 potential, nor an ordinary chemical machine, since there is no suf- 

 ficient explanation of the activity of its chemical processes taking 

 place almost at neutrality. Instead he looks upon the living cell as a 

 thermoelectrical unit based upon an etherial vortex, and the appear- 

 ance of life upon the earth as the appearance of such a vortex acti- 

 vated by a triple movement of centripetal precipitation, of centrifu- 

 gal diffusion, and of ellipsoidal or cylindrical rotation, and sufficiently 

 persistent to construct a body by sweeping along matter in its train 

 and thereafter to engender other vortices specifically like itself. 



These are tenuous speculations at best. It is to the lasting credit 

 of the department of zoology in this university college of Dundee 

 that it gave to the world a reasoned dynamical interpretation of 

 organisms which, working on solid ground, revealed the physical 

 basis of much that had been regarded as manifestations of the pe- 

 culiar properties of life. His presidential address to our Section 

 of the British Association at Portsmouth in 1911 showed that Sir 

 D'Arcy Thompson had already been turning over in his mind the 

 adequacy of the forces of surface tension, elasticity, and pressure to 

 explain a multitude of the phenomena illustrated in the appearances 

 of living things ; but the publication of Growth and Form in 1917 



